"Gluten-free" foods may be contaminated: study

NEW YORK (Reuters Health) - People with celiac disease and others who avoid gluten should beware that foods that are supposed to be naturally gluten-free are often contaminated, warns a new study.

Gluten is a kind of protein found in wheat, barley, and rye. In people with celiac disease - a condition that affects up to about 1 percent of the U.S. population - gluten triggers an immune reaction that causes damage to the small intestine and keeps the body from absorbing nutrients.

Grains such as oats, millet, and rice don't have this protein. But in a new survey of grains, seeds, and flours that should be gluten-free, researchers found that some of these products had picked up traces of gluten - probably from being grown or processed near grains that do naturally contain gluten.

"There was some general assumption (among people with celiac disease) that those naturally gluten-free grains and flours weren't contaminated," Tricia Thompson, a nutrition consultant on celiac disease and the lead author on the study, told Reuters Health.

Thompson and her colleagues analyzed 22 naturally gluten-free grains, seeds, and flours off supermarket shelves, only looking at products that weren't specifically advertised as being gluten-free. They tested the amount of gluten in those products against a proposed Food and Drug Administration limit for any product labeled gluten-free, 20 parts contaminant per million parts product.

Seven of the 22 products wouldn't pass the FDA's gluten-free test - and one product, a type of soy flour, had a gluten content of almost 3,000 parts per million, the authors found. Other products from the sample that weren't truly gluten-free included millet flour and grain, buckwheat flour, and sorghum flour.

The study was too small to give consumers a good idea of how common it is for these products to be contaminated or what products should make people with celiac disease especially wary, Thompson said.

But "it is a red flag," Cynthia Kupper, the executive director of the Gluten Intolerance Group of North America, who was not involved with the research, told Reuters Health.

Even companies that do explicitly label their products as gluten-free, she said, might not always test products they assume won't contain any gluten. The study "is a wake-up call to the food industry," said Kupper. Companies "need to make sure (their products) are truly gluten-free."

Without an FDA regulation in place, there is still no hard-and-fast government definition of what gluten-free means, Thompson said.

That makes it harder to keep companies that might skimp on their testing accountable.

"It's hoped but certainly not assumed that manufacturers who are putting the (gluten-free) label on their single-ingredient grains and flours are testing their ingredients," Thompson said. "Do all manufacturers test? Probably not."

Under the proposed gluten-free labeling rule, the FDA could conduct inspections of manufacturers that claim their products are gluten-free and analyze those products.

Thompson and Kupper agreed that more research needs to be done to find out the scope of the contamination problem. In the meantime, Thompson said, people with celiac disease are probably better off purchasing grains, seeds, and flours with the gluten-free label. The products can't be guaranteed to be completely free of gluten, but it is more likely that they will have been tested, she said.